Patents by Inventor Sadao Akatsuka

Sadao Akatsuka has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4784467
    Abstract: A multi-layered anti-reflection coating for use with a plastic substrate is provided. The coating consists of four layers and has high durability. The first layer furthest from the substrate is made of SiO.sub.2 ; the second layer is made of a mixture of ZrO.sub.2 and TiO.sub.2 ; the third layer is made of ZrO.sub.2 ; and the fourth layer is made of SiO or SiO.sub.2. The optical thicknesses of the first to third layers are about 0.25.lambda. with respect to a design wavelength .lambda., respectively. However the optical thickness of the fourth layer is greater than that of the respective first to third layers and selected between 0.5.lambda. to 2.0.lambda..
    Type: Grant
    Filed: February 13, 1987
    Date of Patent: November 15, 1988
    Assignee: Minolta Camera Kabushiki Kaisha
    Inventors: Sadao Akatsuka, Hakuzo Tani